Term
| what is IUGR? what is the problem with this definition? |
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Definition
| intrauterine growth restriction occurs when the *weight of a fetus is below the 10th percentile*. the growth of the fetus is limited by intrauterine pathology, resulting in an increase of perinatal morbidity and mortality. the problem with this definition is: not all babies in the 10th percentile have IUGR, b/c some of them just have to purely represent that place on the bell curve. therefore, some OBs use 5%, while other use 3%. |
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Term
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Definition
| SGA = small for gestational age, *birth* weight below the 10th percentile |
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Term
| what is the difference between IUGR and SGA? |
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Definition
| IUGR: intrauterine growth restriction. SGA: small for gestational age. IUGR refers to the fetus (obstetricians) while SGA refers to the baby (pediatricians). |
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Term
| what are the three etiologic components of IUGR? |
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Definition
| maternal (diseases/nutrition), placental (transporting substrate), and fetal (infections/anomalies) |
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Term
| what characterizes the maternal medical conditions leading to IUGR? |
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Definition
| anything that clamps down the blood vessels: HTN, renal disease, restrictive lung disease, DM, cyanotic heart disease, antiphospholipid syndrome, collagen-vascular syndrome, hemoglobinopathies, tobacco/substance abuse (smoking risk disappears if you stop before the 2nd trimester, heroin/cocaine/alcohol all increase IUGR risk), and malnutrition (need caloric intake <1500 to affect the baby) |
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Term
| will an increase in caloric intake increase the weight of the baby? |
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Definition
| no, a 20 lb or 70 lb wt gain will still lead to a ~7.5 lb baby |
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Term
| what characterizes the placental etiologies leading to IUGR? |
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Definition
| anything that disrupts flow through the placenta to the baby: PIH, renal disease, essential HTN and any placental or cord abnormalities: primary mosaicism, placenta previa, inappropriate cord insertion. |
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Term
| what characterizes the fetal etiologies leading to IUGR? |
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Definition
| inadequate/altered substrates, congenital abnormalities, and intrauterine infections (listeriosis, TORCH: toxoplasmosis/rubella/CMV/HSV |
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Term
| what are the 2 types of IUGR? |
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Definition
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Term
| what characterizes the symmetric IUGR? |
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Definition
| head to abdominal ratio is normal, but overall weight is decreased (growth of head and body is inadequate). this is seen in congenital anomalies and intrauterine infections (insult happened to the fetus early in pregnancy). |
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Term
| what characterizes the asymmetric IUGR? |
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Definition
| head size is proportionately larger than abdominal size - the *brain is preferentially spared at the expense of the "nonvital" abdominal viscera. this usually occurs late in pregnancy. |
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Term
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Definition
| the correct gestational age is identified, OB hx is assessed, then serial fundal measurements (screening) and serial ultrasounds (w/3-4 wks between) are carried out |
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Term
| what are predictors of IUGR? |
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Definition
| abnormal triple/quad screens (despite normal amniocentesis/US) and elevations of umbilical and uterine artery doppler assessments (increased resistance through placenta to fetus) |
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Term
| what are the biometrics for US IUGR dx? |
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Definition
| biparietal diameter (BPD), head circumference, abdominal circumference, *head to abdominal circumference ratio*, femur length, femur to abdominal ratio, and umbilical/uterine artery doppler |
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Term
| when does the head to abdominal ratio = 1? |
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Definition
| ~ 34 wks, after which the abdomen will start becoming greater than the head (head was previously larger) |
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Term
| what diagnostic methods should detect about 90% of IUGR cases? |
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Definition
| serial ultrasounds and plotting the biometrics. *the 10th percentile is the most commonly used defining point for IUGR* this realistically should be a little lower, b/c there always needs to be some actual representatives of the 10th percentile. the way to differentiate this is between the fetus which is in the 10th percentile the whole gestation vs the fetus who starts out in the 20th and keeps dropping over gestation (the latter is more likely an IUGR case). |
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Term
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Definition
| prenatal care includes severe counseling to discontinue tobacco, drugs, alcohol, and to improve nutritional status. |
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Term
| what is management of IUGR in the antepartum period? |
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Definition
| discontinue tobacco, increase nutritional status, *decrease work load, modified bed rest (up for meals and bathroom - stay on L side to facilitate blood flow to the baby), and antepartum fetal surveillance |
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Term
| what does antepartum fetal surveillance consist of? |
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Definition
| non stress tests (NST), *biophysical profiles (BPP - gold standard, checks: NST, breathing, fluid volume, gross fetal movement, and limb extension for a score of 10)*, and modified BPP. |
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Term
| what are you looking for with antepartum fetal surveillance? |
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Definition
| a balance of fetal lung maturity vs fetal compromise. if constitutionally small w/good antepartum testing - observe (weekly/biweekly BPPs). if the fetus appears unable to thrive in utero (based on fetal testing), it needs to be delivered. |
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Term
| what characterizes the umbilical artery systolic:diastolic ratio in the IUGR fetus? when is this metric used? |
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Definition
| umbilical artery systolic:diastolic ratio in the IUGR fetus is abnormal, with increased resistance to flow and a low, reversed or absent diastolic flow. this is useful in determining necessity of immediate delivery. |
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Term
| what characterizes management of IUGR baby labor and delivery? |
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Definition
| there is a low threshold to induce, an even lower threshold to C-section, electronic fetal monitoring, and a neonatologist/pediatrician needs to be be present. |
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Term
| what is the best thing you can do for IUGR? |
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Definition
| risk factor modification - should start w/preconception counseling if possible. try to get mom into office in under 12 wks. |
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Term
| what does antepartum fetal surveillance tell you? |
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Definition
| how long you can leave the baby in utero (serial US helps you determine weight and if it is dropping off) |
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Term
| when do you deliver an IUGR baby? |
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Definition
| when the risks of remaining in utero outweigh the risks of prematurity |
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Term
| has there been any improvement in decreasing the incidence of IUGR? |
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Definition
| no, but there has been improved management of SGA infants by pediatricians |
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Term
| are present forms of fetal surveillance adequate to predict fetal outcome? |
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Definition
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Term
| what is a big tip of for a possible IUGR case? |
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Definition
| the measurement of the mother between pubis and fundus - if this is off, send for US. if IUGR, modify mom's behavior and get her to rest (blood flow to baby). |
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